Effects of transfer to sea water on standard and routine metabolic rates in smolting Atlantic salmon at different stages of seawater adaptability

• Published in: Journal of Fish Biology
• Main Author: Maxime, V.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: Atlantic salmon
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2002.tb02487.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2002.tb02487.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2002.tb02487.x

Juvenile Atlantic salmon were transferred to sea water at three different times corresponding to different levels of seawater tolerance, i.e. before (A) and at two times (B and C) during the completion of parr‐smolt transformation. Changes in their standard and routine metabolic rates were evaluated by measuring oxygen consumption. The time at which these transfers had been carried out and, consequently, the fish adaptability to sea water affected their post‐transfer metabolism. Indeed, transfer A induced a decrease in mean metabolic rate; under standard conditions, this could be ascribed to a lowered protein turnover. The depression in routine oxygen consumption, which occurred at daylight, was interpreted as an adaptative response to a possible limitation in oxygen supply to the tissues. This limitation would result from a decrease both in the gas diffusing capacity of gills and in oxygen affinity of haemoglobin assumed from changes in plasma ions. Transfers B and C increased standard metabolism; this was probably induced by a stimulation of protein turnover. No outstanding change was noticed in routine oxygen consumption of fish after transfer B. On the other hand, the re‐occurrence of a circadian rhythm of routine metabolism in sea water after transfer C is interpreted as the disappearance of physiological disturbances following a prolonged stay of fish in fresh water.